1. Field of the Invention
This invention relates to processes for producing a fuel additive composition.
2. Description of the Related Art
In U.S. Pat. No. 2,506,539 Mr. Harold Boardman claimed, inter alia, "[a]s an addition agent for gasoline, a mixture of one part by weight of ferrous picrate and about 44 parts by weight of picric acid dissolved in a mixture of methylated spirits and benzene." The disclosure identifies the methylated spirits as grain alcohol, denatured through the addition of a small percentage of wood alcohol, and nine volumes of benzene; observes that the methylated spirits could be replaced with methanol, ethanol, propanol, or mixtures of lower fatty alcohols; and remarks that substitutes for the benzene include toluene. Unfortunately, benzene is toxic; and methylated spirits attack the metallic containers which usually enclose gasoline. The production of this additive creates, moreover, substantial quantities of picratecontaminated barium sulfate waste and exposes those preparing the additive to hazardous barium picrate, ferrous picrate, and other barium and picrate residues.
Richard W. Simmons in U.S. Pat. No. 3,282,858 claimed an improved process for producing the additive, which mainly consists of reacting ferrous sulfate with sodium carbonate in water, removing the precipitated ferrous carbonate, pouring alcohol on the precipitate, adding hydroquinone and picric acid to the resultant alcoholic suspension, drawing alcohol off the ferrous picrate crystals which have then formed, placing these crystals in fusel oil, mixing this solution with a nonoxidizing hydrocarbon solvent in which picric acid has been dissolved, and then adding silica gel. This process is said to be safer since it eliminates dealing with highly hazardous dry ferrous picrate. But it still involves a lengthy process of synthesizing, isolating, and purifying ferrous picrate. Additionally, it generates alcohol waste contaminated with ferrous picrate as well as silica gel waste containing ferrous picrate and picric acid.
In the disclosure for his U.S. Pat. No. 4,073,626, Richard W. Simmons noted that his first patent had, inter alia, reduced the corrosiveness of the Boardman patent by replacing the benzene and that the Boardman additive was unstable. The preferable nitro acid salt in the composition claimed within this second patent by Simmons is ferrous picrate. Although no process is claimed, one example is given for the production of the additive. This example closely follows the process in Simmons's prior patent to the point just prior to alcohol being drawn off the ferrous picrate. Then, instead of removing the alcohol, placing the ferrous picrate crystals in fusel oil, and mixing this solution with a non-oxidizing hydrocarbon solvent in which picric acid has been dissolved, the solution resulting from the ferrous carbonate, picric acid, and isopropyl alcohol simply had 1-nitropropane added to it and was subsequently dissolved in a mixture of isopropyl alcohol and Pacific base oil. Although no isolation and purification of the ferrous picrate was performed, the process is still lengthy and produces alcohol waste.
All claims in the three U.S. Pat. Nos. of Harry Matthew Webb--No. 4,099,930; No. 4,129,421; and No. 4,265,639--involve ferrous sulfate and water, which create an undesirable instability in the additive, increase corrosivity, and limit compatibility of the additive with hydrocarbon fuels. (This is explicit for all claims except numbers 5 and 6 of U.S. Pat. No. 4,099,930, where ferrous sulfate is expressly enumerated as an ingredient but water is not; still, the disclosure for U.S. Pat. No. 4,099,930 indicates that water would be included.)
To solve the problem with instability Myndert T. Scholtz in U.S. Pat. No. 4,265,639 uses EDTA to form an iron (II)/EDTA chelate with all of the +2 iron in the additive and a sufficient amount of an amine to form a picric acid/amine complex with essentially all of the picric acid in the additive. Examples within the disclosure show the source of the +2 iron as being hydrated ferrous sulfate, although the claims are not so limited.
The final patent in this series--U.S. Pat. No. 4,424,063--is a rather unique patent. Most notably, it appears to contain composition of matter claims which do not specify the nature of the composition, but merely state the ingredients utilized to manufacture such composition. The principal disadvantage of the process disclosed, by means of example, for creating this composition is the lengthy period, i.e., twenty-four hours, which the process requires.